The present study aims at providing further insight into the pathogenesis of cytomegalovirus (CMV) infection using the guinea pig as an animal model. Experiments are designed to further define and evaluate specifically congenital CMV infection, persistent infection and reactivation, as well as host immune responses during CMV infection. In addition, means of prevention of CMV infection by vaccination will also be further investigated. Studies of primary CMV infection during various stages of gestation will be centered on the localization of histopathology and CMV antigen in the various tissues of the offspring. Experiments will emphasize the potential for CMV reaction during pregnancy and the influence on the development of fetuses and newborns. In the analysis of host immune responses to CMV infection, delayed skin tests will be used for measuring immunity during maternal and congenital infection. In addition, the effects of CMV infection on guinea pig polymorphonuclear functions will be further investigated. Finally, the potential for both live attenuated and subunit guinea pig CMV vaccine will be assessed in the highly susceptible inbred strain 2 pregnant guinea pig. The possibility of reactivation of guinea pig CMV vaccinated guinea pigs during pregnancy will be further studied. The data obtained will be particularly useful in the control of congenital infection associated wth human CMV infection.